This invention relates to digital signal level shifters.
The purpose of a level shifter is to receive an input digital signal having a given voltage level, and output a second signal at a voltage greater than the input value.
Frequently, the power of the input signal will begin to decrease in value causing a drop in the input lows and highs. Eventually, such input signals lack sufficient power to turn the various switches of the level shifter on or off. As the signal weakens to a given threshold voltage (the voltage required to activate the switches of the level shifter), subsequent high signals which are slightly less than the threshold voltage will not be registered. Additionally, the output of the level shifter will be in one of two different states: constant high, or constant low. The chance of being constant high versus constant low is 50--50.